From bb7f2bc98a3cf3f483d934d53871784b2bbe5204 Mon Sep 17 00:00:00 2001 From: Udit Agarwal Date: Wed, 4 Jul 2018 11:24:49 +0530 Subject: [PATCH] encrypted_keys: Adds support for secure key-type as master key. Encrypted keys can use secure key-type as master key along with trusted/user keys. Secure key as master key uses, secure key type payload derieved using CAAM hardware. Signed-off-by: Udit Agarwal Reviewed-by: Sahil Malhotra --- MAINTAINERS | 1 + security/keys/encrypted-keys/Makefile | 2 + security/keys/encrypted-keys/encrypted.c | 13 ++++++- security/keys/encrypted-keys/encrypted.h | 13 +++++++ .../keys/encrypted-keys/masterkey_secure.c | 37 +++++++++++++++++++ 5 files changed, 64 insertions(+), 2 deletions(-) create mode 100644 security/keys/encrypted-keys/masterkey_secure.c diff --git a/MAINTAINERS b/MAINTAINERS index 0e91c5c8ce56..c9f07180e3ff 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9071,6 +9071,7 @@ F: include/keys/secure-type.h F: security/keys/secure_key.c F: security/keys/securekey_desc.c F: security/keys/securekey_desc.h +F: security/keys/encrypted-keys/masterkey_secure.c KEYS/KEYRINGS: M: David Howells diff --git a/security/keys/encrypted-keys/Makefile b/security/keys/encrypted-keys/Makefile index 7a44dce6f69d..df2b906b7d24 100644 --- a/security/keys/encrypted-keys/Makefile +++ b/security/keys/encrypted-keys/Makefile @@ -7,5 +7,7 @@ obj-$(CONFIG_ENCRYPTED_KEYS) += encrypted-keys.o encrypted-keys-y := encrypted.o ecryptfs_format.o masterkey-$(CONFIG_TRUSTED_KEYS) := masterkey_trusted.o +masterkey-$(CONFIG_SECURE_KEYS) := masterkey_secure.o masterkey-$(CONFIG_TRUSTED_KEYS)-$(CONFIG_ENCRYPTED_KEYS) := masterkey_trusted.o +masterkey-$(CONFIG_SECURE_KEYS)-$(CONFIG_ENCRYPTED_KEYS) := masterkey_secure.o encrypted-keys-y += $(masterkey-y) $(masterkey-m-m) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 60720f58cbe0..5aafaf7e618b 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -36,6 +36,7 @@ #include "ecryptfs_format.h" static const char KEY_TRUSTED_PREFIX[] = "trusted:"; +static const char KEY_SECURE_PREFIX[] = "secure:"; static const char KEY_USER_PREFIX[] = "user:"; static const char hash_alg[] = "sha256"; static const char hmac_alg[] = "hmac(sha256)"; @@ -47,6 +48,7 @@ static unsigned int ivsize; static int blksize; #define KEY_TRUSTED_PREFIX_LEN (sizeof (KEY_TRUSTED_PREFIX) - 1) +#define KEY_SECURE_PREFIX_LEN (sizeof(KEY_SECURE_PREFIX) - 1) #define KEY_USER_PREFIX_LEN (sizeof (KEY_USER_PREFIX) - 1) #define KEY_ECRYPTFS_DESC_LEN 16 #define HASH_SIZE SHA256_DIGEST_SIZE @@ -125,7 +127,7 @@ static int valid_ecryptfs_desc(const char *ecryptfs_desc) /* * valid_master_desc - verify the 'key-type:desc' of a new/updated master-key * - * key-type:= "trusted:" | "user:" + * key-type:= "trusted:" | "user:" | "secure:" * desc:= master-key description * * Verify that 'key-type' is valid and that 'desc' exists. On key update, @@ -140,6 +142,8 @@ static int valid_master_desc(const char *new_desc, const char *orig_desc) if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) prefix_len = KEY_TRUSTED_PREFIX_LEN; + else if (!strncmp(new_desc, KEY_SECURE_PREFIX, KEY_SECURE_PREFIX_LEN)) + prefix_len = KEY_SECURE_PREFIX_LEN; else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) prefix_len = KEY_USER_PREFIX_LEN; else @@ -358,7 +362,7 @@ static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen, enum derived_key_type { ENC_KEY, AUTH_KEY }; -/* Derive authentication/encryption key from trusted key */ +/* Derive authentication/encryption key from trusted/secure key */ static int get_derived_key(u8 *derived_key, enum derived_key_type key_type, const u8 *master_key, size_t master_keylen) { @@ -429,6 +433,11 @@ static struct key *request_master_key(struct encrypted_key_payload *epayload, mkey = request_trusted_key(epayload->master_desc + KEY_TRUSTED_PREFIX_LEN, master_key, master_keylen); + } else if (!strncmp(epayload->master_desc, KEY_SECURE_PREFIX, + KEY_SECURE_PREFIX_LEN)) { + mkey = request_secure_key(epayload->master_desc + + KEY_SECURE_PREFIX_LEN, + master_key, master_keylen); } else if (!strncmp(epayload->master_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) { mkey = request_user_key(epayload->master_desc + diff --git a/security/keys/encrypted-keys/encrypted.h b/security/keys/encrypted-keys/encrypted.h index 1809995db452..f1cb73611e77 100644 --- a/security/keys/encrypted-keys/encrypted.h +++ b/security/keys/encrypted-keys/encrypted.h @@ -16,6 +16,19 @@ static inline struct key *request_trusted_key(const char *trusted_desc, } #endif +#if defined(CONFIG_SECURE_KEYS) +extern struct key *request_secure_key(const char *secure_desc, + const u8 **master_key, + size_t *master_keylen); +#else +static inline struct key *request_secure_key(const char *secure_desc, + const u8 **master_key, + size_t *master_keylen) +{ + return ERR_PTR(-EOPNOTSUPP); +} +#endif + #if ENCRYPTED_DEBUG static inline void dump_master_key(const u8 *master_key, size_t master_keylen) { diff --git a/security/keys/encrypted-keys/masterkey_secure.c b/security/keys/encrypted-keys/masterkey_secure.c new file mode 100644 index 000000000000..87068c966111 --- /dev/null +++ b/security/keys/encrypted-keys/masterkey_secure.c @@ -0,0 +1,37 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 NXP. + * + */ + +#include +#include +#include +#include +#include +#include "encrypted.h" + +/* + * request_secure_key - request the secure key + * + * Secure keys and their blobs are derived from CAAM hardware. + * Userspace manages secure key-type data, but key data is not + * visible in plain form. It is presented as blobs. + */ +struct key *request_secure_key(const char *secure_desc, + const u8 **master_key, size_t *master_keylen) +{ + struct secure_key_payload *spayload; + struct key *skey; + + skey = request_key(&key_type_secure, secure_desc, NULL); + if (IS_ERR(skey)) + goto error; + + down_read(&skey->sem); + spayload = skey->payload.data[0]; + *master_key = spayload->key; + *master_keylen = spayload->key_len; +error: + return skey; +}